Tag category Chem_comp

A preliminary classification used by PDB to indicate that the chemistry of this component while described as clearly as possible is still ambiguous. Software tools may not be able to process this component definition.

Additional text information that is relevant to the data in the current saveframe or to a specific data item in the saveframe. This tag is often used to include information that cannot be associated with a specific tag in the saveframe but is important.

For standard polymer components the one-letter code for the component. If there is not a standard one-letter code for this component or if this is a non-polymer component the one-letter code should be given as 'X'. This code may be preceded by a '+' character to indicate that the component is a modification of a standard component.

For standard polymer components the three-letter code for the component. If there is not a standard three-letter code for this component or if this is a non-polymer component the three-letter code should be given as 'UNK'. This code may be preceded by a '+' character to indicate that the component is a modification of a standard component.